Creping adhesive containing oxazoline polymers

ABSTRACT

A creping adhesive containing about 1% to about 25% polyoxazoline by weight, which imparts softness and resistance to bleaching, to a cellulosic web, and methods of using same are provided.

This is a continuation of U.S. patent application Ser. No. 08/352,371filed on Dec. 8, 1994 now abandoned.

FIELD OF THE INVENTION

This invention relates generally to the field of manufacture of crepingadhesives with application to tissue and toweling products, andparticularly to the properties imparted by creping adhesives to thepaper machine runnabilty and the resulting paper softness.

BACKGROUND OF THE INVENTION

In the manufacture of wet laid facial tissue, bathroom tissue or papertowels, the fibrous web may be creped in order to provide it with thedesired characteristics, such as softness and bulk. The wet crepingprocess involves adhering the web to a rotating creping cylinder, suchas a Yankee dryer, and then removing the adhered web with a doctorblade. The doctor blade impacts the web causing the web to buckle and indoing so ruptures some of the fiber-to-fiber bonds within the web. Theseverity of this creping action depends upon a number of factors,including the degree of adhesion between the web and the surface of thecreping cylinder. Greater adhesion generally causes increased softness.In order to increase the adherence of the fibrous web to the Yankeedryer, a creping adhesive is usually sprayed onto the surface of thecreping cylinder to supplement any natural adhesion the web may havewhen applied to the creping cylinder.

A wide variety of creping adhesives are known in the art. The paperindustry's demand for faster paper machine speeds, less down time due todoctor blade changes and paper breaks, and softer and more uniform papernecessitates development of new and better creping adhesives. Desirablequalities for new and better creping adhesives that will improve papermachine runnability include: increased adhesion, dispersibility, uniformcoating, and resistance to bleach out.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a creping adhesiveconcentrate comprising about 0.01% to about 25% by weight solids,including a polyoxazoline, and a polyamide polymer resin. Preferably,the polyoxazoline is a polyethyloxazoline; and the resin is selectedfrom the resins described below. The creping adhesive of the inventioncoats more evenly, allowing the surface of the paper to be more uniformand improving paper machine runnability. Additionally, this crepingadhesive provides the paper with a higher adhesion than currentlyavailable products.

In another aspect, the invention provides a method for crepingcellulosic paper by applying to a creping cylinder, or the cellulosicstock, the creping adhesive of the invention. When applied the crepingadhesive concentrate of the invention is diluted to contain up to about3% solids.

Other aspects and advantages of the present invention are describedfurther in the following detailed description of the preferredembodiments thereof.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a creping adhesive composition andmethods of use which produce superior paper machine runnability in termsof adhesive strength, dispersibility, and resistance to bleach out inthe creping and drying process of cellulosic webs useful for facialtissue, bathroom tissue, paper towels, or other such products. Bleachout is a decrease in adhesive strength of the creping adhesive due toaddition of bleach in between dye changes.

I. The Creping Adhesive

Thus, the invention provides a creping adhesive concentrate formed ofbetween about 5 to about 25% solids by weight, and preferably about 10%solids by weight. The solids comprise between about 1 weight percent (wt%) to about 5 wt % polyoxazoline, and preferably about 3 wt %polyoxazoline, between about 5 wt % to about 7 wt % polyamide polymer,and the balance water, but not excluding the use of other adjuvantsincluding but not limited to corrosion inhibitors, preservatives, metalsalts (e.g. sodium, potassium, and ammonium salts of borates, oxyanions,and phosphates), and pH adjusters. All percentages provided herein areby weight unless otherwise indicated.

A. The Oxazoline Polymers

The oxazoline polymers according to this invention are water-soluble, orat least dispersible in water at the concentrations employed. Thesepolymers can be either substituted oxazoline homopolymers or copolymers.In either event, the polymers have recurring units of the generalformula ##STR1## where R is any organic radical which does notsignificantly decrease the water-solubility or water-dispersibility ofthe polymers. However, R may be any substituent selected from the groupconsisting of a substituted or unsubstituted aryl group containing from6 to 11 carbon atoms or a substituted or unsubstituted alkyl groupcontaining from 1 to 11 carbon atoms. The substituent R may therefore bealkyl, such as methyl, ethyl, propyl, butyl, isobutyl, etc, or aryl,such as a phenyl group or substituted phenyl group. Preferably, thesubstituent R, in at least about 50 percent of said units, is alkylcontaining from 1 to 11 carbon atoms. Most preferably, the alkyl isethyl. The symbol n is an integer which provides said polymer with amolecular weight of from about 5000 to about 1,000,000, preferably50,000 to 500,000. Generally, n is the molecular weight of the polymerdivided by the molecular weight of the monomer. For example, thepreferred monomer ethyloxazoline, has a molecular weight of 99.13(.sup.˜ 100). When the desired polyethyloxazoline molecular weight isabout 5000, n is about 50; when the desired polyethyloxazoline molecularweight is about 1,000,000, n is about 10,000.

Thus, the polymers used in the creping adhesive may be homopolymers orcopolymers depending upon whether the substituents R are the same forall units of the above formula or are different. In the case ofcopolymers, they may be either heteric or block copolymers.

Particularly preferred oxazoline polymers of this invention arepolyethyloxazolines having molecular weights in the range of about 5000to about 500,000 daltons. Such homopolymers are thermoplastic, amorphoussolids which are water-soluble and have low toxicity. One suchhomopolymer is poly(2-ethyl-2-oxazoline) which has a molecular weight ofabout 500,000 and a structure as follows: ##STR2## where n is about5,000, providing a molecular weight of about 500,000.

The monomers from which the polymers of this invention are formed may beprepared according the procedures described in Chemical Reviews, 71, No.5, pages 483-505 (1971), incorporated herein by reference. Suitableillustrative monomers include 2-methyl, 2-ethyl, and2-isobutyl-2-oxazoline and mixtures of these monomers.

The polymers, whether homopolymers or copolymers, used in the process ofthis invention may be prepared by polymerizing the monomers orcomonomers in a suitable manner. According to U.S. Pat. No. 3,483,141,the monomers may be reacted in an inert atmosphere in the presence of acation catalyst at a temperature of about 20° C. to 250° C. See alsoPolymer Letters, 4, pages 441-445 (1966).

The polymerization temperature preferably is in the range of from about80° C. to 250° C., with reaction times of several hours. These reactiontimes can vary somewhat depending upon the reactants, polymerizationtemperature, catalyst type and concentration, and the desired molecularweight.

Typical of the cationic catalysts which may be used in thepolymerization reaction are alkyl halides such as methyl iodide and1,4-dibromobutane; boron-fluorine compounds such as boron trifluorideetherate, strong acids such as p-toluene sulfonic acid, sulfuric acid,nitric acid and the like. The concentration of catalyst can varyconsiderably so that the mole ratio of monomer to catalyst is from about10:1 to 60,000:1.

B. The Polyamide Resin

The polyamide resin component of the creping adhesive of this inventionmay be included in an amount up to that concentration which producesgel. For example, the polyamide resin may make up between about 1-25 wt% of the total solid content in the creping adhesive concentrate. Thispolyamide resin can be selected readily by one of skill in the art fromamong known and commercially available resins. Suitable resins known tothose of skill in the art include but are not limited to the polyamideresins provided in the Code of Federal Regulations (CFR) 21 parts:§176.170, §175.300 and §176.180, which are incorporated by referenceherein.

Particularly well suited for use in the creping adhesive of theinvention are the polyamide resins described in Munjat, U.S. Pat. No.3,869,342 and U.S. Pat. No. 3,869,343, incorporated by reference herein.One desirable resin has the composition of Table I, which containsapproximately 15% solids. Other polyamide resins described in theselatter patents are also desirable for use in the adhesive compositionsof this invention.

The polyamide resin component of the preferred embodiment is apolyamide-epichlorohydrin resin that has a polyamide base polymerconsisting of the reaction product of itaconic acid, diethylenetriamine,and caprolactam (see Table I part B). The polyamide base polymer is thencrosslinked by epichlorohydrin and the pH adjusted with sulfuric acid toproduce the polyamide-epichlorhydrin resin used in the preferredembodiment (see Table I part A).

                  TABLE I                                                         ______________________________________                                        Part A:                                                                       Components       Percentage, by weight                                        ______________________________________                                        polyamide base polymer                                                                         15-25                                                        H.sub.2 O        60-80                                                        epihalohydrin    1-8                                                          ______________________________________                                    

where the polyamide base polymer contains approximately 50% solids andis formed by the reaction of:

    ______________________________________                                        Part B:                                                                       ______________________________________                                        caprolactam       15-25                                                       H.sub.2 O         21-55                                                       itaconic acid     20-40                                                       diethylene triamine                                                                             15-30                                                       ______________________________________                                    

Desirably, the halogen of the epihalohydrin of these formulations ischlorine. However, other suitable halogens, e.g. bromide, may be readilysubstituted by one of skill in the art. This formulation for a suitablepolyamide resin may be adjusted as needed or desired. For example, oneof skill in the art can readily substitute a suitable polybasiccarboxylic acid, a diacid, or a triacid, for itaconic acid. Examples ofsuitable substitutes include sebacic acid, dodecanedioic acid, dimers ortrimers of oleic acid, reactions with acrylic acid and the like.Similarly, one of skill in the art can readily substitute another aminebase for the exemplified diethylene triamine used in the resin. See 21C.F.R. §176.170, §175.300, and §176.180 for examples of other suitableacids and bases which may be used in the preparation of the resins.

As another example of a polyamide resin formula, one of skill in the artcan readily select an alternative pH adjuster and thus, substituteanother appropriate acid or base capable of adjusting the pH to betweenabout 4 to about 8 for the sulfuric acid (see example 1). One of skillin the art can readily substitute an inorganic acid such as phosphoricacid or an organic acid such as citric acid for the exemplified sulfuricacid used to adjust the pH. Similarly, one of skill in the art canreadily select from among the known preservatives. For example, suitablepreservatives include KATHON®, PABA®, and triazines.

C. Water

The water used in preparing the compositions of the invention ispreferably soft water, i.e., water which is free of calcium andmagnesium, although such soft water is not a requirement. Prior to use,a creping adhesive concentrate of the invention is diluted using waterto about 0.01 percent to about 4 percent solids.

D. Optional Components of Creping Adhesive Concentrate

Other optional components may be readily added into the abovepolyoxazoline and polyamide resin formulations. Such optional componentsmay include, for example, corrosion inhibitors to prevent rust formationof the dryer, such as salts of carboxylic acids and/or sodium nitrite.

Additionally, or as an alternative to adding the optional ingredientsdiscussed above (e.g. pH adjusters, corrosion inhibitors, andpreservatives) into the creping adhesive concentrate, such componentsmay be added at the time of dilution. The pH of the creping adhesiveconcentrate is adjusted to a pH of between 4 and 8, to avoid corrosionof the dryer, desirably, the preferred pH of the creping adhesive of theinvention is 6.

Currently, the presently preferred embodiment of the creping adhesive ofthe invention contains about 7% of the polyamide-epichlorohydrin(anhydrous) resin of Example 1, about 3% polyethyloxazoline with amolecular weight of about 500,000, corrosion inhibitors (preferably 0.6%sebacic acid, 0.55% triethanolamine, and 0.25% monoethanolamine), 0.2%preservative (preferably KATHON®), and the balance water. The additionof 3% polyethyloxazoline has been found to increase the adhesivestrength of the polyamide resin by about 20%. This resultingcomposition, creping adhesive A is described in detail in Example 2 andis about 10±0.5% solids as determined by a conventional evaporationtest, has a pH of between 5.8 and 6.4.

Alternatively, the creping adhesives of the invention may comprisepolyoxazoline with multipolymer systems, rather than the two polymersystems described above. For example, the polyoxazoline may be combinedwith such components as polyvinylamides, polyvinylalcohols (PVA),glyoxylated polyvinylamides, polyethylene oxide, polyethylenimine,polyvinylpyrrolidone, and CARBOWAX® polyethylene glycols. As with otherpolymer systems, polyoxazoline can be readily added into thesemultipolymer systems. Desirable formulations includes a combination ofpolyvinylalcohol and polyethyloxazoline; a combination ofpolyethylenimine and polyethyloxazoline; and a combination of modifiedpolyethylenimine and polyethyloxazoline.

This creping adhesive, and all the adhesives of the invention, are usedby applying it to a creping cylinder, e.g. a Yankee Dryer, or equivalentequipment, for example by spraying directly onto a dryer.

II. Methods of Use

Thus, the present invention provides a method for manufacturing paperproducts. The method of the invention provides improved dispersibility,adhesion, coating and thus, paper machine runnability, i.e., there arefewer problems in paper runs and thus a decrease in the number of timesa machine must be stopped and re-started. Thus, the use of the crepingadhesive of the invention results in more usable paper, which has evenedges and color and fewer holes. The method of the invention alsoimproves resistance to bleach out when paper colors are changed.Improved paper softness may also result.

The method of the invention involves applying the creping adhesives ofthe invention to a creping cylinder or dryer. Preferably, the crepingadhesives of the invention are diluted with water, as defined above, sothat the resulting percentage of solids in the diluted composition areabout 0.1% to about 5% by weight. Alternately, one of skill in the artcould apply the polymers individually or in combination to the crepingcylinder or dryer.

Preferably, the creping adhesives of the invention are applied directlyto a drying cylinder used in the preparation of cellulosic web used tomake tissue products. For example, the creping adhesives are desirablysprayed onto the cylinder, e.g. a Yankee dryer, at a rate of betweenabout 25 to 100 cc/minute, and preferably about 30 cc/minutes, operatingat ambient temperature However, one of skill in the art may adjust thisrate as needed, depending upon such variables such as, e.g., furnish,stock, creping adhesive concentration, other chemicals present, and thedryer conditions.

Optionally, the creping adhesives of the invention may be applied to thedrying cylinder in conjunction with other agents. In one particularlydesired embodiment, the creping adhesive of the invention is applied inconjunction with a release agent. Such release agents are well known tothose of skill in the art. For example such agents may include oils,emulsions, dispersions, and surfactants, which are known to those ofskill in the art.

Typically, the creping adhesive and release agent are sprayed usingseparate feed lines and either the same or different spray booms. Duringapplication, adjustments in the concentrations of these components aremade based upon visual inspection of the dryer, sensory equipmentanalysis of the dryer and paper during the run, and analysis of theresulting paper. Advantageously, it has been found that the crepingadhesive of the invention requires the use of a smaller amount ofrelease agent than do conventional, known creping adhesives.

The following examples illustrate the preferred methods for preparingand using the creping adhesives of the invention. These examples areillustrative only and do not limit the scope of the invention.

EXAMPLE 1 Preparation of a Polyamide Resin

The following provides the components of a preferred polyamide resin inthe order in which these components are reacted together.

                  TABLE II                                                        ______________________________________                                        Part A:                                                                       Components:      Percentage, by weight                                        ______________________________________                                        Polyamide base polymer                                                                         20.8                                                         H.sub.2 O        74.2                                                         epichlorohydrin  4.6                                                          H.sub.2 SO.sub.4 0.2                                                          preservative     0.2                                                                           100.0,                                                       ______________________________________                                    

where the polyamide base polymer contains approximately 50% solids andis formed by the reaction of:

    ______________________________________                                        Part B:                                                                       ______________________________________                                        caprolactam      17.98%                                                       H.sub.2 O        26.41                                                        itaconic acid    31.02                                                        diethylene triamine                                                                            24.59                                                                         100.00                                                       ______________________________________                                    

The polyamide-epichlorohydrin resin and the polyamide base polymer wereprepared using the processes described in U.S. Pat. No. 3,869,342 andU.S. Pat. No. 3,869,343.

EXAMPLE 2 Preparation of a Creping Adhesive

An exemplary creping adhesive of the invention, creping adhesive A, wasprepared as follows.

To a reactor, which has top agitation and is equipped with a nitrogengas inlet for the bottom of the tank, with was charged with about 37.2%polyamide-epichlorohydrin resin of Example 1 and soft water. Then acorrosion inhibitor consisting of about 0.6% sebacic acid, about 0.55%triethanolamine, and about 0.25% monoethanolamine were added, in order.The mixture was heated to 100° F. and mixed until fully dissolved. ThepH was adjusted, if necessary, to about 6.1±0.3 with sebacic acid ormonoethanolamine. While mixing, about 3 wt % of the 500,000 MWpolyethyloxazoline was added and blended until all of the polyoxazolinehad fully dissolved. The mixture was then sampled to confirm that it wasa clear, amber liquid, having a pH (neat) between 5.8-6.4, and 10.0±0.5%solids. The mixture was then drawn through a 40-80 mesh strainer.

EXAMPLE 3 Trial on Tissue Machine

A creping adhesive prepared according to Example 2 was compared with acommercially available creping adhesive (not containingpolyethyloxazoline). The machine used was a suction breast roll machinewhich makes exclusively 9.2#(basis weight) two ply bathroom tissueproducts.

A. Test A--Prior Art Run

To repair a low spot in the dryer, the mill had to spray metalize thefront edge of the dryer with a stainless steel coating. Shortlyafterwards, a continuous creping system was installed. The continuouscreping system is designed for use with an index blade steel. Soon afterthe installation of the creping system, the system was found to beunable to run in the continuous mode due to a rough area where thestainless steel was bonded to the cast iron. As the blade contacted thefront edge, it became worn and caused drag marks on the sheet and tearson the front edge.

The mill attempted to solve this problem using other commerciallyavailable adhesive products as instructed by the manufacturer to attemptto obtain improvement in the ability to run the continuous blade system.

B. Test B

Creping adhesive A, prepared as described in Example 2 above, and arelease agent comprising emulsifiable mineral oil [Houghton] were usedin this test run.

The conditions for the run were as follows.

Fabric--LINDSAY®, run for one week;

Felt--ALBANY®, run for 30 days;

Refiners--80 AMPs;

Crepe angle--16° C.;

Blade bevel--0

Set up angle--11/8

Basis weight--9.1

Wire speed--4615 FPM (feet per min)

Reel speed--3649 FPM

Yankee Steam Pressure--140 pounds per square inch (psi)

Yankee steam rate--25 psi/hour

Yankee Differential--13.2

Wet End Hood--686° F.

Dry End Hood--686° F.

Crepe Blade Pressure--45 psi

Coating--30 cc/min

Release 40 cc/min

Average Yankee surface Temperature--190° F.

During the trial the machine was taken through a variety of colorchanges and subsequent bleach out. The effect on the coating wasnegligible. In contrast, under these conditions, other, commerciallyavailable, polyamide resin adhesives would be removed from the dryer.

EXAMPLE 4 Adhesive Strength Tests

This example provides data showing the adhesive strength of exemplarycreping adhesives of the invention as measured on the Tinius-OlsenTesting Machine Model 5000 [Tinius Olsen Testing Machine Co.; WillowGrove, Pa.] by a 180° Peel Test Method, which is a modification of theASTM method D903.

A. Sample Preparation:

1. Steel plates [Catalog No. 101-A-2, SAE 1010 cold rolled heavy gaugesteel plates, Metaspec Co.; San Antonio, Tex. or equivalent] weresubmerged in a petroleum ether bath for at least 2 hours to remove therust preventative coating. The plates were then washed with CERFAK® 1400surfactant, rinsed with acetone, and then air-dried.

2. 1"×8" non-woven fabric strips (cut from interfacing; 30% naturalcellulose/70% polyester, Staple Sewing Aids Corp., N.J.) were cut fromthe bulk interfacing material such that all strips were cut in the samedirection and so that the same side of the fabric adhered to the metalplate.

3. The fabric strips were placed in the test solutions and thoroughlysoaked for at least 15 minutes. A minimum of two strips was run persample.

After soaking, the fabric strips were removed from the solution andallowed to drip off. Next the strips were placed onto the metal surfaceso that one end of the fabric strip was flush with the edge of the metalplate. The strip was centered.

The fabric strip was smoothed onto the metal surface such that no airbubbles formed under the fabric strip. A "fabric tail" of 3 inchesserved as the end placed into the testing machine's upper clamp.

4. The fabric coated plate was then placed onto a preheated (15 minutesminimum) Corning Hot Plate Stirrer (model #PC351) on setting 4 (480° F.)for four minutes (the thinner plates were cured on low (180°-200° F.)for four minutes). After heating, the sample was allowed to cool to roomtemperature. The fabric "tail" may be blotted to hasten its drying.

5. The sample plate was placed in the testing machine's lower clamp,after first debonding about 1" of the bound fabric from the metal plate.The fabric "tail" was 180° from the upper clamp. The "tail" was thenplaced into the testing machine's upper clamp such that it was bent backupon itself.

6. Tinius Olsen Machine Settings:

Force=50%=2.50 lbs.

Ext.=100=5.0 in.

Speed=2.50 in./min.

7. The Tinius Olsen Testing Machine evenly pulled the fabric strip fromthe metal plate while simultaneously recording the adhesive force anddistance the cross-hair has travelled.

8. Adhesive strength measurements were reported as Force per width ofadhesive strip. Force measurements were between 15-85% of load cellweight.

The purpose of the Peel Test is to test additives and alterations to thecreping adhesives of the invention. Adhesive strength was related to theeffectiveness of the Yankee Dryer creping process. A linear responsebetween force and % adhesive was obtained for the polyamide resin ofExample 1.

B. Adhesion Study A

To demonstrate that the components of the invention are synergistic, notadditive in effect, dual samples of the polyamide resin of Example 1with (a) polyethyloxazoline low molecular weight (approx. 50,000), (b)polyethyloxazoline having a molecular weight of approx. 200,000 MW or(c) polyethyloxazoline having a molecular weight of approx. 500,000 MW,were run on the above-described test. In addition, blanks of eachversion of polyethyloxazoline (no polyamide resin) were run. Theadhesive strength data are provided in Table III below.

                  TABLE III                                                       ______________________________________                                                             Adhesive Strength                                                             Pounds per inch                                          ______________________________________                                        Polyamide Resin        1.377                                                  Polyamide Resin + 1% polyethyloxazoline                                                              1.416                                                  (50,000 MW)                                                                   1% polyethyloxazoline (50,000 MW)                                                                    0                                                      Polyamide Resin + 1% polyethyloxazoline                                                              1.590                                                  (200,000 MW)                                                                  1% polyethyloxazoline (200,00 MW)                                                                    0                                                      Polyamide Resin + 1% polyethyloxazoline                                                              1.700                                                  (500,000 MW)                                                                  1% polyethylxazoline (500,000 MW)                                                                    0                                                      ______________________________________                                    

The polyamide resin of Example 1 only and polyethyloxazoline onlycontrols were run. None of the polyoxazoline only control solutionsproduced a test sample with any adhesion. Each combination of thepolyamide resin of Example 1 and a polyethyloxazoline demonstratedincreased adhesion in comparison to a control containing only thepolyamide resin of Example 1. The composition containingpolyethyloxazoline (500,000 MW) version showed the greatest increase inadhesive strength.

C. Adhesion Study B

The purpose of this test was to evaluate a higher concentration ofpolyethyloxazoline in the creping adhesive of the invention. Thiscreping adhesive contained the polyamide resin of Example 1 compositionin combination with 5 wt % polyethyloxazoline. The resulting data areprovided in Table IV below.

                  TABLE IV                                                        ______________________________________                                                             Adhesive Strength                                                             Pounds per inch                                          ______________________________________                                        Polyamide Resin        1.31                                                   Polyamide Resin + 1% polyethyloxazoline                                                              1.70                                                   (500,000 MW)                                                                  Polyamide Resin + 5% polyethyloxazoline                                                              1.79                                                   (500,000 MW)                                                                  ______________________________________                                         The 5% polyethyloxazoline sample had greater adhesion than the 1%             polyethyloxazoline sample.                                               

Numerous modifications and variations of the present invention areincluded in the above-identified specification and are expected to beobvious to one of skill in the art. Such modifications and alterationsto the compositions and processes of the present invention are believedto be encompassed in the scope of the claims appended hereto.

What is claimed is:
 1. A creping adhesive concentrate consistingessentially of about 1 percent to about 25 percent of an oxazolinepolymer by weight and a polyethyleneimine.
 2. The creping adhesiveconcentrate according to claim 1, wherein the oxazoline polymer has therepeating unit: ##STR3## where R is selected from the group consistingof an aryl group containing from 6 to 11 carbon atoms or an alkyl groupcontaining from 1 to 11 carbon atoms, and n is an integer which providessaid polymer with a molecular weight of from about 5000 to about1,000,000.
 3. The creping adhesive according to claim 2, wherein themolecular weight of the oxazoline polymer is between about 50,000 toabout 500,000.
 4. The creping adhesive according to claim 1 wherein theoxazoline polymer is polyethyloxazoline.
 5. The creping adhesiveaccording to claim 4 wherein the polyethyloxazoline has a molecularweight of about 500,000.
 6. The creping adhesive according to claim 1wherein said oxazoline polymer is present in an amount of about 3percent by weight.